Journal of Pediatric Surgery (2007) 42, 2120–2122
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Transmural intrathoracic lipoma with intraspinal extension Vishesh Jain a , Arbinder K. Singal a , Arun K. Gupta b , Veereshwar Bhatnagar a,⁎ a
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi 110029, India Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi 110029, India
b
Received 11 June 2007; revised 1 August 2007; accepted 9 August 2007
Index words: Intrathoracic lipoma; Chest wall defect; Intraspinal extension
Abstract A rare case of transmural dumbbell intrathoracic lipoma with intraspinal extension is reported. Preoperative diagnosis was possible with a computed tomographic scan and fine-needle aspiration cytology. Complete excision was curative. The chest wall defect was repaired with Prolene mesh. Only one similar case has been previously reported in the English literature. © 2007 Elsevier Inc. All rights reserved.
Lipomas are ubiquitous and can occur anywhere in the body. Thoracic lipomas are uncommon benign lesions in the pediatric age group; transmural dumbbell lesions are even more infrequent, and those with spinal extension are extremely rare. Radiologic investigations help in making the diagnosis but cannot rule out malignancy. Complete surgical excision is curative and provides histologic certainty about the benign nature of the tumor.
1. Case report A 4-year-old girl presented with a painless, gradually enlarging swelling in the right upper back. She had recurrent episodes of nonproductive cough with fever, but there were no neurologic complaints. The general examination revealed a 6 × 4–cm soft swelling in the right paraspinal region, medial to the scapula and extending partly under the scapula (Fig. 1). Cough impulse was
⁎ Corresponding author. E-mail address:
[email protected] (V. Bhatnagar). 0022-3468/$ – see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2007.08.045
present. Air entry was decreased on the right side. Neurologic examination result was normal. Plain chest xray revealed a soft tissue mass lifting up the scapula, widening of the third intercostal space, and extension into the right hemithorax (Fig. 2). There was no calcification in the mass and no erosion of ribs. Noncontrast computed tomographic scan showed a 7 × 6 × 6–cm fat-density lesion in the right subscapular region extending into the right thorax through the third intercostal space, displacing the mediastinum to the left with partial atelectasis of the right upper lobe (Fig. 3). Small intraspinal extension at the level of the third dorsal lumbar vertebra was noted to be causing widening of intervertebral foramen with extension into the extradural space. Fine-needle aspiration cytology revealed fibroadipose tissue in a background of inflammatory infiltrate, suggestive of lipoma. The patient was explored through a right posterolateral thoracotomy via the bed of the fourth rib, revealing a huge lipomatous mass, partly extrathoracic, extending into the thorax through third intercostal space and into the spinal canal via the third intervertebral foramina (Fig. 4). The mass was well defined, with no invasion into the surrounding structures. The mass was completely resected along with the intraspinal extension. The defect in between the splayed ribs was repaired by a Prolene mesh. Histopathologic examination demonstrated
Intraspinal extension in transmural thoracic lipoma
Fig. 1 Right paraspinal swelling extending beneath the right scapula.
a lipoma. The patient had an uneventful recovery and remains asymptomatic on follow-up.
2. Discussion Intrathoracic lipomas are uncommon benign lesions and only rarely have been described in the pediatric age group. These tumors are usually single and involve both sides of thorax with same frequency [1-3]. The most widely used classification is by Keeley and Vana [4] and Williams and Parsons [5]. They divided intrathoracic lipoma in 2 classes: (1) intrathoracic, or completely within the thoracic cavity, and (2) hourglass or dumbbell types that have both intra-and extrathoracic lesions. These are further divided into (i) cervicomediastinal type, which passes through thoracic inlet, and (ii) transmural type, which passes through intercostal space and rarely through the sternum.
Fig. 2 Chest x-ray postero-anterior view showing a soft tissue mass extending into the right hemithorax with widening of the third intercostal space.
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Fig. 3 Noncontrast computed tomographic scan showing transmural hourglass intrathoracic lipoma with intraspinal extension at the level of the third thoracic vertebra.
Intraspinal extension of a dumbbell lipoma has been rarely described—only one case of a transmural intrathoracic lipoma with intraspinal extension in a pediatric patient has been reported [6]. A cervicomediastinal dumbbell lipoma with intraspinal extension in a pediatric patient has also been reported [7]. These neoplasms are slow growing and may reach great proportions without producing symptoms. The most common symptom is a nonproductive cough and a feeling of pressure at the site of the tumor. The cervicomediastinal group is most likely to give early symptoms, even with small tumors. When a tumor produces massive collapse of the lung or encroaches upon a main bronchus, dyspnea appears. This dyspnea can be of such severity as to cause death [8]. Malignant degeneration into liposarcoma is of some theoretical concern; however, there are no reports of this having occurred. Computed tomographic scan achieves identification of the fatty tumor component, characterized by low-grade density, but it does not distinguish between various adipose
Fig. 4 Operative view of a huge lipomatous dumbbell mass extending into the thorax through the third intercostal space.
2122 tumors. However, infiltration of surrounding structures rather than displacement may suggest liposarcoma, and presence of a fibrovascular network during contrast enhancement may suggest lipoblastoma. Magnetic resonance imaging is occasionally indicated if there is a large intraspinal component or if there are symptoms and signs of nerve root/spinal cord compression. In the case under review, magnetic resonance imaging was not expected to provide further information. Definitive diagnosis can only be achieved by pathologic examination, which must differentiate between lipoma, lipoblastoma, hibernoma, and liposarcoma; the last 2 are very rare in childhood. In general, the diagnosis is not established until surgical resection has been performed. Although these tumors are benign, resection is necessary to unequivocally establish the diagnosis, alleviate symptoms, and prevent local recurrence. Aggressive evaluation and complete surgical excision have been recommended for these unusual lesions. Complete surgical removal, particularly of the intraspinal component, may be challenging. In general, a knuckle of tissue entering the vertebral foramina, as in the case under review, usually does not need any complex surgical approach and can be excised via the thoracotomy. But if the intraspinal component of the tumor is large, infiltrative, or causing neural compression, then a prior neurosurgical approach via a laminectomy may be indicated either as a separate intervention or under the same anesthesia.
V. Jain et al. The other challenge is in the reconstruction of the chest wall defect, which is necessary for the stability and physiologic kinetics of the chest wall. Simple approximation of the ribs may be sufficient if the defect is small and if the ribs are not deformed. However, if the defect is large, as in the case under review, then fascial or rib grafts, synthetic mesh, or other prosthetic materials can be used for chest wall reconstruction.
References [1] Krause LG, Ross CA. Intrathoracic lipomas. Arch Surg 1962;84:444-8. [2] Shawker TH, Dennis JM, Nilprabhassorn P. Benign intrathoracic lipoma with rib erosion in an infant. Radiology 1972;104:111-2. [3] Johansson L, Soederlund S. Intrathoracic lipoma. Acta Chir Scand 1963;126:558-65. [4] Keeley JL, Vana AJ. Collective reviews: lipomas of the mediastinum— 1940-1955. Int Abst Surg 1955;103:313-22. [5] Williams WT, Parsons WH. Intrathoracic lipomas. J Thorac Surg 1957; 33:785-90. [6] Maier HC. Extradural and intrathoracic lipoma causing spinal cord compression. Successful treatment by surgical excision. JAMA 1962; 181:610-2. [7] Waldehausen JHT, Rodgers BM, Silen ML. Pediatric intrathoracic lipoma. Pediatr Surg Int 1993;8:248-50. [8] Leopold RS. A case of massive lipoma of the mediastinum. Arch Int Med 1920;26:274-8.
